This invention relates to a ski shoe sole.
More specifically, the invention is concerned with a ski shoe sole of a type which can be associated with ski bindings, comprising a rear automatic release assembly having a pusher element adapted for releasably engaging with a recess in the rear portion of the shoe heel and acting in the longitudinal direction of the shoe, and a front automatic release assembly having an engagement element detachably cooperating with a peg or nail located under the toe portion of the shoe sole. Ski bindings of the kind referred to above also comprise, as disclosed in the U.S. Pat. No. 4,353,574 by this same Applicant a substantially rigid rod-like element which is connected pivotally to the rear release assembly and partially encircles the skier's leg for transferring side thrust forces from the skier's leg to the ski.
A shoe for a ski binding of this type behaves substantially as a soft shoe because it has no longer to serve as a rigid element for transmitting forces from the skier's leg to the ski.
Accordingly, the shoe may be used, not only for skiing but also for walking. The sole of such a shoe should, however, possess adequate strength on account of its being stressed in the longitudinal direction by a compressive force which is applied substantially in the sole main plane and due to the rear pusher element biasing the sole toward the front release assembly. Inadequate strength would result in the sole being flexed under compression and the shoe being released from its binding, or at least in preventing proper engagement of the shoe with the binding in normal skiing conditions.
On the other hand, too stiff a sole would defeat a comfortable deambulation and the advantages of using a soft shoe afforded by the binding.
An attempt has been made to strengthen the shoe at the foot hollow region by disposing a substantially plate-like reinforcing element between the shoe upper and top of the sole. That approach has proved substantially successful in meeting such conflicting requirements, but poses practical construction problems which make implementation of the shoe as a whole more expensive and complicated.
Another problem encountered with the shoes in question is that of firmly anchoring the peg in the sole, which again involves a sufficiently rigid sole construction, while posing some significant practical manufacturing problems.